/Engine/Source/Runtime/CoreUObject/Public/Misc/PackageName.h
Checks if a package can be found using known package extensions (header extensions only; files with the extensions of other segments are not returned).
true if the package could be found on disk.
static bool FindPackageFileWithoutExtension ( const [FString](API\Runtime\Core\Containers\FString) & InPackageFilename, [FString](API\Runtime\Core\Containers\FString) & OutFilename )